Method for fabricating thin film transistor, method for fabricating array substrate, and a display apparatus

ABSTRACT

The present application provides a method for fabricating a thin film transistor, a method for fabricating an array substrate, and a display apparatus. A method for fabricating a thin film transistor including: providing a substrate; covering an isolating layer on the substrate; coating an active layer precursor solution on the isolation layer; forming an active layer thin film by the active layer precursor solution; dividing the active layer thin film into a small module active layer, the mobility of the active layer of the thin film transistor is increased, and to drive the quantum dot light emitting device of the array substrate through the thin film transistor with high mobility to improve the display luminescence performance of the display apparatus.

FIELD OF THE INVENTION

The present application relates to a display technology field, and moreparticularly to a method for fabricating thin film transistor, methodfor fabricating array substrate, and a display apparatus.

BACKGROUND OF THE INVENTION

Quantum dot light emitting device, QLED is a new kind of displayapparatus similar to the principle and structure of the organic lightemitting display, OLED, that is the quantum dot and organic/inorganicsemiconductor are a kind of flat panel display apparatus driven byexternal direct current electric field and the exciton recombination toemitting light. The quantum dots are adapted as the light emitting layerof QLED having a wider adjustable spectral, higher luminous intensity,higher color purity, longer fluorescence life, better environmentalstability than the organic fluorescent dyes, so has a broaderdevelopment prospect compared with OLED. In recent years, thetransparent amorphous oxide semiconductor, TAOS thin film transistors,

TFTs have received extensive attention from their potential applicationsin active matrix light emitting diode displays. The conventionalamorphous silicon TFTs cannot meet the current-driven type OLED/QLEDdisplay panel due to the low mobility and the severe threshold voltagedrift. Although the polysilicon TFTs have higher mobility and betterstability, the high temperature process and excessive process steps makethe production cost extremely high, and its grain boundary makes thepoor uniformity, thus affecting its application in large-size display.TAOS TFTs not only have very low current leakage, but also visible lightand transparent, good uniformity, good stability, specifically can beprepared at low temperature, is expected to achieve low-cost of theflexible display. However, the mobility of the oxide TFTs is lower thanthat of the polycrystalline silicon, so it is of great practicalsignificance to improve the mobility of the oxide thin film transistors.

Because of its excellent and unique electrical and optical properties ofthe carbon nanotubes, CNTs, in recent years, its application in theelectronic devices field is more and more in-depth. Semiconductorsingle-walled carbon nanotubes, SWCNTs are considered to be one of themost valuable electrical materials due to their excellent mechanical,thermal, electrical properties and chemical stability, which can be usedin high-frequency devices to improve the frequency response range ofdevices. In addition, as the size of conventional Si semiconductordevices keeps decreasing, some unavoidable constraints continue toemerge, such as the short channel effect, the fluctuation of thestatistics of the doping concentration in small size cause theuniformity of the quality of the device, and SWCNTs can be used tofabricate the n-type or p-type transistors used in integrated circuitswithout doping, it is possible to replace silicon-based semiconductors.The mobility of the SWCNTs or nanotube array are basically above 1000cm²/(V.s), to meet the requirement of the high mobility of thetransistor. Therefore, how to improve the mobility of the thin filmtransistor, and drive the quantum dot light emitting device through thehigh mobility thin film transistor to improve the display luminescenceperformance of the display apparatus has become an urgent problem in theindustry.

SUMMARY OF THE INVENTION

The technical problem that the present application mainly solves is toprovide a method for fabricating a thin film transistor, a method forfabricating an array substrate and a display apparatus to improve themobility of the thin film transistor and to drive the quantum dot lightemitting device through the high mobility thin film transistor toimprove the display luminescence performance.

In order to solve the above-mentioned technical problems, a technicalaspect of the present application is to provide a method for fabricatingthe thin film transistor including the steps of:

-   -   providing a substrate;    -   covering an isolating layer on the substrate;    -   coating an active layer precursor solution on the isolation        layer, the active layer precursor solution formed of a        combination of a metal oxide and carbon nanotubes;    -   forming an active layer thin film by the active layer precursor        solution; and dividing the active layer thin film into a small        module active layer.

In order to solve the above-mentioned technical problems, another aspectof the present application is to provide a method for fabricating thearray substrate including a method for fabricating the thin filmtransistor and a method for fabricating a quantum dot light emittingdevice of each pixel unit:

The method for fabricating the thin film transistor is produced by anyof the methods described above.

In order to solve the above-mentioned technical problems, another aspectof the present application is to provide a display apparatus, includingan array substrate, a color filter substrate disposed opposite to thearray substrate, and a color filter substrate provided on the arraysubstrate and the color filter substrate, wherein the array substrateincludes a thin film transistor including a substrate, an isolationlayer disposed on the substrate, and an active layer disposed on theisolation layer, the active layer being made of a metal oxide and carbonnanotubes.

The present application has the advantages is that, comparing to theconventional technology, the method for fabricating the thin filmtransistor, the method for fabricating the array substrate and thedisplay apparatus of the present application are obtained by mixing asingle-walled carbon nanotube and a metal oxide as an active layer of athin film transistor to increase the mobility, and driving the quantumdot light emitting device through the high mobility thin film transistorto improve the display luminescence performance of the displayapparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the embodiments of the presentapplication or prior art, the following FIG.s will be described in theembodiments are briefly introduced. It is obvious that the drawings aremerely some embodiments of the present application, those of ordinaryskill in this field can obtain other FIG.s according to these FIG.swithout paying the premise.

FIG. 1 is a schematic flow diagram of a method for fabricating a thinfilm transistor of the present application;

FIG. 2 is a schematic diagram of a precursor solution and an activelayer of the present application;

FIG. 3 is a schematic perspective view of the active layer in FIG. 1 ina thin film transistor;

FIG. 4 is a schematic structural view of a thin film transistor of thepresent application;

FIG. 5 is a schematic flow diagram of a method for fabricating a quantumdot light emitting device in an array substrate according to the presentapplication;

FIG. 6 is a schematic structural view of a quantum dot light emittingdevice in the array substrate of the present application;

FIG. 7 is a schematic cross-sectional view of the quantum dot lightemitting device of FIG. 6;

FIG. 8 is a schematic diagram of the driving circuit of the quantum dotlight emitting device of FIG. 6; and

FIG. 9 is a schematic structural view of a display apparatus accordingto the present application.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Embodiments of the present application are described in detail with thetechnical matters, structural features, achieved objects, and effectswith reference to the accompanying drawings as follows. It is clear thatthe described embodiments are part of embodiments of the presentapplication, but not all embodiments. Based on the embodiments of thepresent application, all other embodiments to those of ordinary skill inthe premise of no creative efforts acquired should be considered withinthe scope of protection of the present application.

Specifically, the terminologies in the embodiments of the presentapplication are merely for describing the purpose of the certainembodiment, but not to limit the invention.

In the drawings, the thickness of the layers and regions is exaggeratedin order to clarify the device. The same reference numerals denote thesame elements throughout the drawings.

It will also be understood that when an element is referred to as being“over” or “upper” on another element, it can be disposed directly on theother element, or an intermediate element can also be present.

Referring to FIGS. 1 and 4, the method for fabricating the thin filmtransistor of the present application includes the steps of:

Step S1: providing a substrate 11.

Specifically, the substrate 11 can be glass, plastic, quartz or silicon,and the material of the substrate in other embodiments is not limitedthereto.

Step S2: covering an isolating layer 12 on the substrate 11.

wherein, the specifically to cover the isolating layer 12 on thesubstrate 11 is: covering the isolation layer 12 on the substrate 11 bya chemical vapor deposition.

In other embodiments, the material of the isolating layer 12 can be oneor a combination of Al₂O₃, HfO₂, ZrO₂, SiO₂, SiN_(x), or an organiccompound.

Step S3: coating an active layer precursor solution on the isolationlayer 12, and the active layer precursor solution is formed of acombination of a metal oxide and carbon nanotubes.

Wherein, referring to FIG. 2, coating the active layer precursorsolution on the isolating layer is specifically carried out by addingthe single-walled carbon nanotubes to ethylene glycol monomethyl etherto form an A solution with uniform dispersion by ultrasound; dissolvingall of the indium chloride, gallium chloride hydrate, zinc chloride andethanolamine in ethylene glycol monomethyl ether, wherein the ratio ofethanolamine to indium, gallium and zinc is 10:1:1:1, the mixture isstirred at 50° C. for 1 hour in the air environment, and is placed in 24hours to form a B solution; the A solution is added to the B solution ata different mass ratio of single-walled carbon nanotubes/metal oxides(SWCNTs/IGZO) and dispersed for 2 hours by ultrasound to form ahomogeneous mixed active layer precursor solution.

Wherein the material of the metal oxide can be one or a combination ofZnO, IZO, IGZO, ZTO, HIZO or In₂O₃.

Step S4: forming an active layer thin film 13 by the active layerprecursor solution.

Wherein, referring to FIG. 3, the specifically step of forming an activelayer thin film by the active layer precursor solution is: impregnatingthe substrate 11 covered with the isolation layer 12 with acetone,methanol and isopropanol; the substrate 11 is ultrasonically cleaned andblown dry by high-purity nitrogen; spin-coating the active layerprecursor solution onto the isolation layer 12, pre-baking at 80° C. for5 minutes in air, and followed by heating to 350° C. for 40 minutes,removing the organic solvent and rapidly annealing to obtain an activelayer 13 thin film.

Step S5: dividing the active layer 13 thin film into a small moduleactive layer.

Wherein the specifically dividing the active layer 13 thin film into asmall module active layer is: coating a photoresist on the active layer13 thin film; exposing, developing, wet etching the photoresist todivide the active layer 13 thin film into a small module active layercorresponding to each of the thin film transistor.

When the thin film transistor includes a source electrode 14 and a drainelectrode 15, the method for fabricating the thin film transistorfurther includes a process of fabricating the source electrode and thedrain electrode, the specifically process is: forming the sourceelectrode 14 and the drain electrode 15 on the isolation layer 12, andthe source electrode 14 and the drain electrode 15 are located on bothsides of the active layer 13 and are connected to the active layer 13,the specifically is to deposit a metal layer on the isolation layer 12by physical vapor deposition, applying photoresist on the metal layer,and then exposing, developing, wet etching to form the source electrode14 and the drain electrode 15.

The thin film transistor further includes a gate electrode 17 and a gateinsulating layer 16. The above-mentioned fabricating method furtherincludes a step of forming the gate electrode 17 and the gate insulatinglayer 16, covering the gate insulating layer 16 on the active layer 13and the source electrode 14 and the drain electrode 15, specifically,the covering of the gate insulating layer 16 is by chemical vapordeposition.

Forming the gate electrode 17 on the gate insulating layer 16,specifically, a metal layer is deposited on the gate insulating layer 16by the physical vapor, and a photoresist is applied on the metal layer,then exposing, developing, wet etching to form the gate electrode 17,and the formed thin film transistor at this time is a top gate type thinfilm transistor.

Wherein the material of the gate electrode 17, the source electrode 14,and the drain electrode 15 can be one or a combination of Mo/Ti, Mo/Cu,Mo/Au, Mo/Al, Cr/Au, Cr/Cu. The material of the gate insulating layer 16can be one or a combination of Al₂O₃, HfO₂, ZrO₂, SiO₂, SiN_(X) or anorganic compound.

When the thin film transistor is a bottom gate type, the specificallystructure of the thin film transistor of the bottom gate type is thegate insulating layer above the gate electrode, the active layer abovethe gate insulating layer, the source electrode and the drain electrodelocated above the active layer.

It should be noted that, the method for fabricating the thin filmtransistor further includes a step of forming a passivation layer andforming a contact hole (not shown) on the passivation layer,specifically is covering a passivation layer on the gate insulatinglayer and the gate electrode, specifically by coating the passivationlayer by a chemical vapor deposition, and applying a photoresist on thepassivation layer, then exposing, developing, dry etching thepassivation layer and the gate insulating layer to form the contact holecorresponding to the region of a drain electrode pattern.

Wherein the material of the passivation layer can be one or acombination of Al₂O₃, HfO₂, ZrO₂, SiO₂, SiN_(X) or an organic compound.

Referring to FIG. 5, is a schematic flow diagram of a method forfabricating a quantum dot light emitting device in an array substrateaccording to the present application. Wherein the array substrate issimilar to the conventional technology, includes a substrate and aplurality of pixel units arranged in a matrix distributed on thesubstrate, each of the pixel units includes at least one thin filmtransistor, the thin film transistor is the thin film transistorprovided by the embodiment described above, the array substrate furtherincludes a quantum dot light emitting device located at each of thepixel unit.

Wherein the substrate of the array substrate can be a glass substrate ora flexible substrate. When the substrate is a flexible substrate, theflexible substrate is made of a polymer material such as a polyvinylalcohol thin film, a polyimide thin film, or a polyester thin film. Themethod for fabricating the array substrate includes a method forfabricating the thin film transistor in a pixel unit and a method forfabricating the quantum dot light emitting device.

Wherein the method for fabricating the thin film transistor is themethod for fabricating the thin film transistor provided in the aboveembodiment, and the method for fabricating the quantum dot lightemitting device will be described in detail below.

Referring to FIGS. 6 and 7, a quantum dot light emitting device can beformed on the basis of the thin film transistor provided in the aboveembodiment, and the method for fabricating the quantum dot lightemitting device specifically includes the steps of:

Step S1: forming an anode pattern 10 on the substrate on which the thinfilm transistor is formed, and the anode 10 is connected to the drainelectrode of the thin film transistor. The specifically to form theanode pattern on the substrate on which the thin film transistor is:forming a transparent conductive film by sputtering on the substrate onwhich the thin film transistor is formed, and forming a transparentpixel anode by photolithography and wet etching to form a transparentpixel anode by isolating the transparent conductive film patterncorresponding to each thin film transistor. And then ultrasound washingby deionized water, acetone and isopropanol for 15 minutes, dried at100° C. and treated with an ultraviolet ozone machine for 30 minutes toclean and improve the hydrophilicity of the surface of the transparentconductive film.

Wherein the material of the anode 10 can be one or a combination ofdoped graphene, metal film (Al, Ag, Pt, Au, etc.), oxide (ITO, AZO, CTO,etc.), composite film (TiO₂-Ag-TiO₂, SiO₂-Au-ZrO₂, etc.), transparentconductive polymer (polyaniline, etc.)

Step S2: forming a hole injection layer 20 pattern on the substrate onwhich the pattern of the anode 10 is formed.

The specifically of forming the hole injection layer pattern on thesubstrate on which the anode 10 pattern is formed includes spin-coatingthe aqueous dispersion solution of poly-3,4-vinyl dioxythiophene andpolystyrene sulfonate on the substrate having an anode 10 pattern for 60seconds at a rotational speed of 3000 revolutions per minute, heating ina glove box at 200° C. for 10 minutes to remove aqueous and thermallycross-linked to obtain a hole injection layer 20.

Wherein the material of the hole injection layer 20 can be one or acombination of PEDOT (PSS), 2T-NATA, or m-MTDATA.

Step S3: forming a hole transport layer 30 pattern on the substrate onwhich the hole injection layer 20 pattern is formed.

The specifically of forming the hole transport layer pattern on thesubstrate on which the hole injection layer pattern is formed includesspin-coating a solution of the polymer triphenyl diamine derivative onthe hole injection layer 20 to form the hole transport layer 30.

Wherein the material of the hole transport layer 30 can be one or acombination of TFB, PVK, CBP, NPB or Poly-TPD.

Step S4: forming a light emitting layer 40 pattern on the substrate onwhich the hole transport layer 30 pattern is formed.

The specifically of forming the light emitting layer pattern on thesubstrate on which the hole transport layer pattern is formed includesspin-coating quantum dot of CdSe/ZnS dissolved in toluene on the holetransport layer 30 at a rotational speed of 2000 revolutions per minutefor 20 seconds to form a quantum dot light emitting layer, and dried ina vacuum oven at 150° C. for 10 minutes to form a light emitting layer40 pattern.

Wherein the material of the light emitting layer 40 can be one or acombination of carbon quantum dot, graphene quantum dot, cadmium-basedquantum dot (CdSn/ZnS, CdTe, etc.), cadmium-free quantum dot (InP,perovskite quantum dot, etc.) or silicon quantum dot.

Step S5: forming an electron transport layer 50 pattern on the substrateon which the light emitting layer 40 pattern is formed.

The specifically of forming the electron transport layer pattern on thesubstrate on which the light emitting layer pattern is formed includesplacing the substrate on which the light emitting layer 40 is formed ina vapor deposition machine, thermally depositing a layer of a holeblocking layer having a thickness of 40 nm to form the electrontransport layer 50.

Wherein the material of the electron transport layer 50 can be one or acombination of TPBi, BBOT, BCP, Alq3 or BND.

Step S6: forming a cathode 60 pattern on the substrate on which theelectron transport layer 50 pattern is formed.

The specifically of forming the cathode pattern on the substrate onwhich the electron transport layer pattern is formed includes covering ametal mask, depositing aluminum on the substrate on which the electrontransport layer 50 is formed by a vacuum deposition method to obtain alattice pattern to form a cathode 60. The cathode 60 is connected to thecathode grounded power source (not shown) via a through hole (not shown)to form an electric field with the anode to drive the light emittinglayer to emit light.

Wherein the material of the cathode 60 can be one or a combination ofdoped graphene, single layer metal (Al, Ag, Mg, etc.), alloy (Mg: Ag,Li: Al, etc.) or a double layer (thin insulating layer plus metal, suchas LiF, MgO, Al₂O₃ plus Al, etc.).

It should be noted that, the method for fabricating the quantum dotlight emitting device can further include a method of forming aperipheral protective layer on the cathode 60 covering the entiresubstrate, for example, by coating a layer of resin by a resin coatingtechnique, and then performing a patterning process to form theperipheral protective layer on the corresponding region to preventdamaging to the pixel electrode and/or the light emitting organic matterby the air, moisture and other impurities.

In addition, the method for fabricating the thin film transistorprovided in the embodiment of the present application, each film layeris formed mainly by sputtering or coating, and the patterning process,the process flow is simple and the requirements for the equipment arelow, and the equipment for preparing the amorphous silicon thin filmtransistor can be adapted to fabricate the thin film transistor having ahigher carrier mobility, the production cost of the product can bereduced.

The patterning process in the present application can only include aphotolithographic process or include a photolithographic process and anetching step, and can also include other processes for forming apredetermined pattern, such as printing, inkjet, etc., photolithographyprocess refers to using photoresist, mask plate, exposing machine andother processes to form patterns during the processes of film forming,exposing, developing and other processes. The corresponding patterningprocess can be selected according to the structure formed in the presentapplication.

Referring to FIG. 8, the driving circuit of the quantum dot lightemitting device includes a first controllable switch T1, a secondcontrollable switch T2, and a quantum dot light emitting device.Wherein, a control terminal of the first controllable switch T1 receivesa scanning signal Vscan from the scanning line of the scanning drivingcircuit, and a first terminal of the first controllable switch T1receives a data signal Vdata from the data line, a second terminal ofthe first controllable switch T1 is connected to a control terminal ofthe second controllable switch T2, a first terminal of the secondcontrollable switch T2 is connected to the anode 10 of the quantum dotlight emitting device, a second terminal of the second controllableswitch T2 receives a voltage signal VDD. Wherein the first controllableswitch Ti and the second controllable switch T2 are N-type thin filmtransistors, the control terminals, the first terminals and the secondterminals of the first and second controllable switches respectivelycorrespond to the gate electrodes, the drain electrodes and sourceelectrodes of the N-type thin film transistors.

When the scanning signal Vscan is at a high level, the firstcontrollable switch T1 is turned on, the high level of the data signalVdata is provided to the control terminal of the second controllableswitch T2, the second controllable switch T2 is turned on, the voltagesignal VDD supplies a voltage to the quantum dot light emitting deviceto make it emitting light.

Referring to FIG. 9, is a schematic structural view of the displayapparatus of the present application. The display apparatus includes theabove-described array substrate, a color filter substrate disposedopposite to the array substrate, and a liquid crystal disposed betweenthe array substrate and the color filter substrate, other devices andthe functions of the display apparatus are the same with the devices andfunctions of the display apparatus in the current technology, and willnot be described here.

The method for fabricating the thin film transistor and the method forfabricating the array substrate increase the mobility by mixing thesingle-walled carbon nanotube and the metal oxide as the active layer ofthe thin film transistor and driving the quantum dot light emittingdevice through the high mobility thin film transistor to improve theluminous performance of the display.

Above are embodiments of the present application, which does not limitthe scope of the present application. Any modifications, equivalentreplacements or improvements within the spirit and principles of theembodiment described above should be covered by the protected scope ofthe invention.

1. A method for fabricating a thin film transistor, comprising:providing a substrate; covering an isolating layer on the substrate;coating an active layer precursor solution on the isolation layer, theactive layer precursor solution formed of a combination of a metal oxideand carbon nanotubes; forming an active layer thin film by the activelayer precursor solution; and dividing the active layer thin film into asmall module active layer.
 2. The method for fabricating the thin filmtransistor according to claim 1, wherein the step of coating the activelayer precursor solution on the isolation layer, the active layerprecursor solution formed of a combination of a metal oxide and carbonnanotubes comprises: adding single-walled carbon nanotubes to ethyleneglycol monomethyl ether to form an A solution with uniform dispersion byultrasound; dissolving all of indium chloride, gallium chloride hydrate,zinc chloride and ethanolamine in ethylene glycol monomethyl ether,wherein a ratio of ethanolamine to indium, gallium and zinc is 10:1:1:1,stirred at 50° C. for 1 hour in an air environment, and placed in 24hours to form a B solution; and mixing the A solution and the B solutionat different mass ratios, and dispersed for 2 hours by ultrasound toform a homogeneous mixed active layer precursor solution.
 3. The methodfor fabricating the thin film transistor according to claim 1, whereinthe step of forming the active layer thin film by the active layerprecursor solution comprises: impregnating the substrate covered withthe isolation layer with acetone, methanol and isopropanol;ultrasonically cleaning the substrate and followed blown drying byhigh-purity nitrogen; spin-coating the active layer precursor solutiononto the isolation layer, pre-baking at 80° C. for 5 minutes in air, andfollowed heating to 350° C. for 40 minutes, removing an organic solvent,and rapidly annealing to obtain an active layer thin film; wherein thestep of dividing the active layer thin film into the small module activelayer comprises: coating a photoresist on the active layer thin film;and exposing, developing, wet etching the photoresist to divide theactive layer thin film into a small module active layer corresponding toeach of the thin film transistor.
 4. The method for fabricating a thinfilm transistor according to claim 1, wherein the method furthercomprises: fabricating a source electrode and a drain electrode on theisolation layer, and the source electrode and the drain electrodeconnected to the active layer, specifically depositing a metal layer onthe isolation layer by physical vapor deposition, applying a photoresiston the metal layer, and exposing, developing, wet etching to form thesource electrode and the drain electrode; covering a gate insulatinglayer on the active layer, the source electrode and the drain electrode,specifically covering the gate insulating layer by chemical vapordeposition; forming a gate electrode on the gate insulating layer,specifically depositing the metal layer on the gate insulating layer bythe physical vapor deposition, and applying the photoresist on the metallayer, exposing, developing, wet etching to form the gate electrode;covering a passivation layer on the gate insulating layer and the gateelectrode, specifically coating the passivation layer by the chemicalvapor deposition; and forming a contact hole, specifically applying thephotoresist on the passivation layer, exposing, developing, dry etchingto form the contact hole.
 5. A method for fabricating an arraysubstrate, wherein the method comprises a method for fabricating thethin film transistor in each pixel unit and a method for fabricating aquantum dot light emitting device; wherein the method for fabricatingthe thin film transistor is according to the method recited in claim 1.6. The method for fabricating the array substrate according to claim 5,wherein the method for fabricating the quantum dot light emitting devicecomprises: forming an anode pattern on the substrate on which the thinfilm transistor is formed, and the anode is connected to the drainelectrode of the thin film transistor; forming a hole injection layerpattern on the substrate on which the pattern of the anode is formed;forming a hole transport layer pattern on the substrate on which thehole injection layer pattern is formed; forming a light emitting layerpattern on the substrate on which the hole transport layer pattern isformed; forming an electron transport layer pattern on the substrate onwhich the light emitting layer pattern is formed; and forming a cathodepattern on the substrate on which the electron transport layer patternis formed.
 7. The method for fabricating the array substrate accordingto claim 6, wherein the step of forming the anode pattern on thesubstrate on which the thin film transistor comprises: forming atransparent conductive film by sputtering on the substrate on which thethin film transistor is formed, and forming a transparent pixel anode byphotolithography and wet etching by isolating the transparent conductivefilm pattern corresponding to each thin film transistor; and ultrasoundishing by deionized water, acetone and isopropanol for 15 minutes,drying at 100° C. and treating with an ultraviolet ozone machine for 30minutes to clean and improve the hydrophilicity of the surface of thetransparent conductive film; wherein the step of forming the holeinjection layer pattern on the substrate on which the anode pattern isformed comprises: spin-coating the aqueous dispersion solution ofpoly-3,4-vinyl dioxythiophene and polystyrene sulfonate on the substratehaving an anode pattern for 60 seconds at a rotational speed of 3000revolutions per minute, heating in a glove box at 200° C. for 10 minutesto remove aqueous and thermally cross-linked to obtain a hole injectionlayer; wherein the step of forming the hole transport layer pattern onthe substrate on which the hole injection layer pattern is formedcomprises: spin-coating a solution of the polymer triphenyl diaminederivative on the hole injection layer to form the hole transport layer;wherein the step of forming the light emitting layer pattern on thesubstrate on which the hole transport layer pattern is formed comprises:spin-coating quantum dots of CdSe/ZnS dissolved in toluene on the holetransport layer at the rotational speed of 2000 revolutions per minutefor 20 seconds to form a quantum dot light emitting layer, and drying ina vacuum oven at 150° C. for 10 minutes to form a light emitting layerpattern; wherein the step of forming the electron transport layerpattern on the substrate on which the light emitting layer pattern isformed comprises: placing the substrate on which the light emittinglayer is formed in a vapor deposition machine, thermally depositing alayer of a hole blocking layer having a thickness of 40 nm to form theelectron transport layer; and wherein the step of forming the cathodepattern on the substrate on which the electron transport layer patternis formed comprises: covering a metal mask, depositing aluminum on thesubstrate on which the electron transport layer is formed by a vacuumdeposition method to obtain a lattice pattern to form a cathode.
 8. Adisplay apparatus, comprising an array substrate, a color filtersubstrate disposed opposite to the array substrate, and a liquid crystaldisposed between the array substrate and the color filter substrate,wherein the array substrate comprises a thin film transistor, the thinfilm transistor comprises a substrate, an isolating layer is disposed onthe substrate and an active layer is disposed on the isolating layer,the active layer is formed by a combination of a metal oxide and carbonnanotubes.
 9. The display apparatus according to claim 8, wherein theactive layer is formed by adding the single-walled carbon nanotubes toethylene glycol monomethyl ether to be an A solution with uniformdispersion by ultrasound; dissolving all of the indium chloride, galliumchloride hydrate, zinc chloride and ethanolamine in ethylene glycolmonomethyl ether, wherein a ratio of ethanolamine to indium, gallium andzinc is 10:1:1:1, stirred at 50° C. for 1 hour in the air environment,and placed in 24 hours to form a B solution; and mixing the A solutionand the B solution at a different mass ratio, and dispersing for 2 hoursby ultrasound to form a homogeneous mixed active layer precursorsolution.
 10. The display apparatus according to claim 8, wherein thearray substrate further comprises a quantum dot light emitting device,the quantum dot light emitting device comprises: an anode, a holeinjection layer, a hole transport layer, a light emitting layer, anelectron transport layer and a cathode sequentially disposed, whereinthe anode is disposed on the substrate of the thin film transistor, andthe anode is connected to the drain electrode of the thin filmtransistor.